Inferno Novel by Dan Brown. Inferno is a mystery thriller novel by American author Dan Brown and the fourth book in his Robert Langdon series, following Angels & Demons, The Da Vinci Code and The Lost Symbol. Harvard symbologist Robert Langdon awakes in a hospital bed with no recollection of where he is or how he got there. Nor can he explain the origin of the macabre object found hidden in his belongings. A threat to his life will propel him and a young doctor, Sienna Brooks, into a breakneck chase across the city to save it from deadly global plot. Dan Brown has raised the bar yet again, combining classical Italian art, history, and literature with cutting-edge science in this sumptuously entertaining thriller.